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Percents/Transcript
Transcript Title text reads: The Mysteries of Life with Tim and Moby Tim is relaxing on the beach. TIM: Sure is nice to be doing... nothing. Moby, an orange robot, approaches with some travel brochures. He beeps. TIM: What's this? Moby hands Tim a piece of paper with a list of activities and times. TIM: A schedule? Well I… I sorta wanted to, uh… to relax. Moby crosses one activity, bird watching, off the list. A letter appears. Text reads as Tim narrates: Dear Tim and Moby, how do I find percents? From, Wally. TIM: Again, I was pretty sure we were supposed to be on vacation here. Moby beeps. TIM: You're right. A percent is a ratio that compares a number to 100. A label appears, reading, percent. TIM: The word, percent, means hundredths, or parts per 100. I’d sorta like to find out what percent of our day will be used up doing all of these activities. On-screen, the schedule appears. TIM: According to Moby, we’ll be up at 6 a, m and in bed at 10 p m. That leaves us with 16 hours of awake time. Let's see… Says here we're supposed to fish from 6 a, m to 9 a, m. That's 3 hours, so the fishing part of our day can be expressed as three-sixteenths. A fraction appears, reading, three-sixteenths. TIM: That’s 3 hours of fishing out of 16 hours that we’re awake. Now, I can think of 3 different ways to make three-sixteenths into a percent. Let's try the first way: setting up a proportion. A label appears, reading, proportion. TIM: Three-sixteenths equals x, one-hundredths. An equation appears, reading, three-sixteenths equals x, over 100. TIM: See, here we're comparing the 2 ratios; if 16 were equivalent to 100, then what would 3 equal? To solve the proportion we use a trick called multiplying cross products. On-screen, the cross products are multiplied: 16 times x, and 3 times 100. TIM: We make these cross products equal to each other, then solve the equation. An equation appears, reading, 16 times x, equals 3 times 100. The equation becomes, 16 times x, equals 300. Both sides are divided by 16, leaving the answer, x, equals 18.75. TIM: X, equals 18.75. And 18.75 over 100 is the same as saying 18.75 percent. An equation appears, reading, 18.75 over 100 equals 18.75 percent. TIM: So 18.75 percent of our awake time will be spent fishing. Moby beeps. TIM: Right. Moby says that 25 percent of our day should be devoted to hiking. We could set up a proportion again, but let's try a different method. 25 percent equals 25 one-hundredths, which is also equal to 0.25. An equation appears, reading, 25 percent equals 25 over 100, equals 0.25. TIM: We can multiply 0.25 by 16 to find 25 percent of 16. And 0.25 times 16 hours equals 4 hours. That’s 4 hours of hiking. An equation appears, reading, 0.25 times 16 equals 4. Moby beeps. TIM: From 5 to 6 p m we’re swimming. Moby beeps. TIM: You got it: 1 hour swimming out of 16 hours total is one-sixteenth. A fraction appears, reading, one-sixteenth. TIM: The third way to find percents is to convert ratios to their decimal form. And one-sixteenth in decimal form is 0.0625. An equation appears, reading, one-sixteenth equals 0.0625. TIM: We multiply that by 100 to convert it to a percentage... and that’s 6.25 percent of our day. An equation appears, reading, 0.0625 times 100 equals 6.25 percent. Moby beeps. TIM: That's three different ways to work with percentages. Depending on the information you have, one way may be better than the others. It's up to you to decide. Moby beeps. TIM: Oh believe me, I was getting to that. Let's calculate the amount of free time that’s left over. We can add up all of the percents we found: 25 percent plus 6.25 percent, plus 18.75 percent, equals 50 percent. An equation appears, reading, 25 percent plus 6.25 percent, plus 18.75 percent, equals 50 percent. TIM: And we subtract that from our total of 100 percent… And we’ll have 50 percent of our day left over for free time. An equation appears, reading, 100 percent minus 50 percent equals 50 percent. TIM: That's me doing absolutely nothing. That's 8 hours, by the way: 50 percent of 16. This could work. Moby beeps and holds up more brochures. TIM: Basket weaving? Canoe building? Hula dancing? I don't dance. Well, maybe I dance a little. Category:BrainPOP Transcripts Category:BrainPOP Math Transcripts